OBJECTIVES: To investigate the clinical and immunological features of children with primary immune thrombocytopenia (pITP) or connective tissue disease (CTD) with thrombocytopenia as the initial manifestation at initial diagnosis, and to provide a basis for early differentiation. METHODS: A retrospective study was performed on 236 children with pITP (pITP group) or CTD with thrombocytopenia as the initial manifestation (CTD-TP group) who were admitted from January 2019 to August 2024. Clinical and immunological indicators were compared between the two groups to identify potential influencing factors for early differentiation and their discriminative validity. RESULTS: Compared with the pITP group, the CTD-TP group had a significantly older age of onset and significantly lower leukocyte count, eosinophil count, lymphocyte count, and complement C4 level (P<0.05), as well as significantly higher levels of C-reactive protein, IgE, and IgM (P<0.05). The logistic regression analysis showed that age, IgE, IgM, total B cells, and complement C4 were predictive factors for early differentiation between pITP and CTD-TP (P<0.05). The receiver operating characteristic curve analysis showed that a combination of these five factors had a good discriminative validity, with an area under the curve of 0.944. The correlation analysis showed a negative correlation between IgG and platelet count in the pITP group (r_s=-0.363, P<0.05) and a positive correlation between NK cells and platelet count in the CTD-TP group (r_s=0.713, P<0.05). CONCLUSIONS There is heterogeneity in the clinical and immunological indicators between children with pITP and CTD-TP at initial diagnosis, and these research findings can help with the early differentiation between the two diseases.
Purpura, Thrombocytopenic, Idiopathic/immunology* ; Diagnosis, Differential ; Connective Tissue Diseases/immunology* ; Retrospective Studies ; Early Diagnosis ; Age of Onset ; Leukocyte Count ; Complement C4/immunology* ; C-Reactive Protein/immunology* ; Immunoglobulin E/immunology* ; Immunoglobulin M/immunology* ; Humans ; Male ; Female ; Infant ; Child, Preschool ; Child ; Adolescent ; Biomarkers/blood*

Immune thrombocytopenia (ITP) is a hemorrhagic autoimmune disease characterized by antibody-mediated platelet injury. ITP has complicated immunopathological mechanisms that need further elucidation. It is well known that the costimulatory molecules OX40 ligand (OX40L) and OX40 play essential roles in the immunological mechanisms of autoimmune diseases. Previously, we discovered that the expression of OX40L and OX40 is significantly increased in the peripheral blood mononuclear cells (PBMCs) of ITP patients. In our present study, OX40L-induced follicular helper T (Tfh) cells exhibited an activated phenotype with elevated expression of inducible T-cell costimulator (ICOS), programmed cell death protein-1 (PD-1), and cluster of differentiation 40 ligand (CD40L) in vitro. Moreover, aberrant OX40L‒OX40 expression might promote the Tfh1-to-Tfh2 shift in vivo, inducing the generation of autoantibodies by enhancing the helper function of Tfh cells for B lymphocytes in a mouse model, which might accelerate the progression of ITP. Additionally, signal transduction through the OX40L‒OX40 axis might be related to the activation of tumor necrosis factor receptor-associated factor (TRAF)‒nuclear factor-κB (NF-κB) and Janus kinase (JAK)‒signal transducer and activator of transcription (STAT) signaling pathways. Overall, OX40L‒OX40 signaling is proposed as a potential novel therapeutic target for ITP.
Animals ; OX40 Ligand/physiology* ; Purpura, Thrombocytopenic, Idiopathic/immunology* ; Cell Differentiation ; Mice ; T-Lymphocytes, Helper-Inducer/cytology* ; T Follicular Helper Cells/cytology* ; Signal Transduction ; Receptors, OX40 ; Mice, Inbred C57BL ; Humans ; Female

OBJECTIVE: To study the correlation of IL-37 with T lymphocytes subsets and NK cells in ITP patients, and to explore its possible mechanisms involved in the pathogenesis of ITP. METHODS: Forty-five patients with newly diagnosed ITP(newly diagnosed group), 32 patients of complete remission (remission group) and 22 healthy persons(control group) were selected. The serum level of IL-37 in 3 groups was determined by enzyme linked immunosorbent assay (ELISA). The mRNA expression of IL-37, IL-17 and IL-18 in peripheral blood mononuclear cells（PBMNC） in 3 groups was measured by real-time fluorescence quantitative polymerase chain reaction (PCR). The number of IL-18RαCD4 T cells and Tim-3NK cells in the peripheral blood in 3 groups was detected by flow cytometry (FCM). RESULTS: The serum level of IL-37 in the peripheral blood of ITP patients in the newly diagnosed group was significantly higher than that in the control group and the remission group(P＜0.01) . The expression level of IL-37 in PBMNC of the ITP patients in newly diagnosed group was higher than that in the control group and the remission group(P＜0. 05). The expression level of IL-17 and IL-18 in PBMNC of the ITP patients in newly diagnosed group was higher than that in the control group and the remission group(P＜0. 01); the expression of IL-18Rα in CD4 T cells in newly diagnosed group was significantly higher than that in both the control and the remission group(P＜0.01).The expression of Tim-3 in NK cells in ITP patients was significantly lower than that in the control group (P＜0. 01). In ITP patients, the serum IL-37 level and IL-18RαCD4T cells ratio both negatively correlated with Plt count (r=-0.58, r=-0.48) moreo-ver the serum IL-37 level also negatively correlated with amount of CD4 T cells and NK cells (r=-0.29, r=-0.28), but positively correlated with amount of CD8 T cells (r=0.329). CONCLUSION The IL-37 and its receptors may play an immunoregulatory role in CD4 T cells and NK cells, the IL-37 may be a therapeutic target for ITP patients.
CD8-Positive T-Lymphocytes ; Flow Cytometry ; Humans ; Interleukin-1 ; immunology ; Killer Cells, Natural ; Leukocytes, Mononuclear ; Purpura, Thrombocytopenic, Idiopathic ; T-Lymphocyte Subsets

OBJECTIVETo explore the role of Treg cells in the pathogenesis of idiopathic thrombocytopenic purpura (ITP).

METHODSThe ITP mouse model was established, the Treg cell ratio in peripheral blood and spleen was detected by flow cytometry, the CD4+ CD25+ T cells were sorted by immunomagnetic beads, the Treg cell associated transcription factors (Foxp3, Smad7, STAT5 and Akt-1) and cytokines (IL-10, TGF-β) in CD4+ CD25+ T cells were enriched from spleen mononuclear cells, and the mRNA expression of Treg cell was measured by real-time PCR.

RESULTSThe ratio of Tregs in peripheral blood and spleen decreased significantly in ITP mouse, as compared with the controls (P<0.01). In addition, the mRNA expression of IL-10, TGF-β and Foxp3 decreased significantly in spleen CD4+ CD25+ T cells (P<0.05). Expression of Smad 7 mRNA was higher than that of controls.

CONCLUSIONThe alteration in Treg frequency and function may be responsible for the immune dysfunction in ITP disease. It is also speculated that the lower mRNA expression of Foxp3 and higher mRNA expression of Smad 7 may inhibit the proliferation and differentiation of Treg cells.

Animals ; Flow Cytometry ; Forkhead Transcription Factors ; metabolism ; Interleukin-10 ; metabolism ; Mice ; Purpura, Thrombocytopenic, Idiopathic ; immunology ; pathology ; RNA, Messenger ; metabolism ; Real-Time Polymerase Chain Reaction ; Smad7 Protein ; metabolism ; Spleen ; cytology ; T-Lymphocytes, Regulatory ; cytology ; Transforming Growth Factor beta ; metabolism

OBJECTIVETo investigate the significance of Th17/Treg imbalance in the development and treatment of primary immune thrombocytopenia (ITP) in children.

METHODSThirty-two children diagnosed with ITP between May and August, 2015 and 22 healthy children were enrolled. Flow cytometry was used to determine the Th17/Treg ratio in peripheral blood of healthy children and children with ITP before and after treatment with immunoglobulin.

RESULTSCompared with the patients with ITP before treatment, the healthy children and the patients treated with immunoglobulin had a significantly lower percentage of Th17 cells in CD4+ T cells, a significantly lower Th17/Treg ratio, and a significantly higher percentage of Treg cells in CD4+ T cells in peripheral blood (P<0.05). In the 32 ITP children treated with immunoglobulin, 20 had complete response, 4 had response, and 8 had no response. The patients with complete response had a significantly lower percentage of Th17 cells in CD4+ T cells and a significantly lower Th17/Treg ratio in peripheral blood than the patients without response (P<0.05).

CONCLUSIONSThe Th17/Treg imbalance can be found in children with ITP. Immunoglobulin can improve the cellular immune function by regulation of the Th17/Treg ratio. The Th17/Treg ratio may serve as an indicator for assessing the therapeutic effects of ITP.

Child ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Purpura, Thrombocytopenic, Idiopathic ; immunology ; T-Lymphocytes, Regulatory ; immunology ; Th17 Cells ; immunology

OBJECTIVETo detect platelet anti-HPA-1a and -1b antibodies using recombinant GPIIIa fragments coupled to Luminex beads.

METHODSThe sensitivity of 2 techniques, monoclonal antibody specific immobilization of platelet antigen (MAIPA) and Luminex bead assay, was compared using 12 twofold-serial dilutions (from neat to 1 in 2048) of an anti-HPA-1a WHO international standard. The specificity of Luminex assay to identify anti-HPA-1a and -1b antibodies was assessed using 8 negative or positive controls and 36 blinded samples provided by WHO Platelet Workshop.

RESULTSThe sensitivity of MAIPA and Luminex bead assay to detect anti-HPA-1a was dilution 1/64 (i.e. 1.56 IU/ml) and far more than dilution 1/2048 (i.e. 0.049 IU/mL), respectively. The Luminex bead assay could specifically identify negative and positive controls of anti-HPA-1a and -1b. All results of 36 blinded samples by Luminex assay were accordant to reference results except one sample which contained high concentration antithetical antibody and resulted in false positive of anti-HPA-1b. Cross-reactivity was also not observed with the samples containing HLA, ABO or other platelet antibodies.

CONCLUSIONThe Luminex beads coupled with recombinant GPIIIa fragments can be used to detect HPA-1 system antibodies with sufficient sensitivity and specificity, that is suitable for the detection of platelet alloantibodies in clinical alloimmune thrombocytopenia.

Antibodies, Monoclonal ; Antigens, Human Platelet ; immunology ; Blood Platelets ; Humans ; Integrin beta3 ; chemistry ; Isoantibodies ; blood ; Purpura, Thrombocytopenic, Idiopathic ; diagnosis ; Recombinant Proteins ; chemistry ; Sensitivity and Specificity

OBJECTIVETo investigate the influence of divalent cation chelator EDTA and heparin sodium on the detection of ITP platelet-specific autoantibodies by the modified monoclonal antibody immobilization of platelet antigen assay (MAIPA) and to explore the relationship between types of platelet specific autoantibodies and glucocorticoid efficacy.

METHODSThe samples were obtained from EDTA- and heparin- anticoagulant ITP patients, respectively, so as to detect the platelet-specific autoantibodies (GPIIb/IIIa and GPIbα) in 140 ITP samples by modified MAIPA, then the differences between these two methods were compared.

RESULTSOut of 140 cases in EDTA group, 55 cases were positive for GPIIb/IIIa, while 76 cases in heparin group were positive for GPIIb/IIIa, 42 cases in both group were repeatable; among them 13 cases were positive in EDTA group and negative in heparin group, while 34 cases were positive in heparin group and negative in EDTA group, there was significant difference between them (x (2) = 9.38, P < 0.05), 62 cases in 140 cases of EDTA group were positive for GPIba, while 51 cases in heparin group were positive for GPIba, 42 cases in both group were repeatabe; among them 20 cases were positive in EDTA group and negative in heparin group, while 9 cases were positive in heparin group and negative in EDTA group, there was no significant difference between them (x (2) = 3.44, P > 0.05). A total of 320 cases received a standard glucocorticoid treatment, out of them 143 cases were positive for GPIbα with effective rate 39.9%, 177 cases were negative for GPIbα with effective rate 79.7%, there was statisticalty significant difference between them (x (2) = 53.115, P < 0.05).

CONCLUSIONEDTA anticoagulant (a divalent cation chelator) has a significant influence on detection of ITP platelet-specific autoantibodies (GPIIb/IIIa) by a modified MAIPA method and the GPIbα antibody positive may be one of the important factors that results in un-sensitivity of ITP patients to glucocorticoid treatment.

Antibodies, Monoclonal ; Anticoagulants ; therapeutic use ; Antigens, Human Platelet ; Autoantibodies ; blood ; Blood Platelets ; immunology ; Fibrinolytic Agents ; Glucocorticoids ; therapeutic use ; Heparin ; Humans ; Platelet Glycoprotein GPIIb-IIIa Complex ; Purpura, Thrombocytopenic, Idiopathic ; blood ; immunology

Humans ; Immune Tolerance ; Purpura, Thrombocytopenic, Idiopathic ; immunology ; T-Lymphocytes ; immunology

OBJECTIVETo study the expression of leukocyte-associated Ig-like receptor-1(LAIR-1) in children with immune thrombocytopenia (ITP), in order to explore the possible role of LAIR-1 in the pathogenesis of childhood ITP.

METHODSExpression levels of LAIR-1 on CD4(+) T cells, CD8(+) T cells and CD19(+)CD20(+) B cells of peripheral blood were measured in 40 children with ITP by flow cytometry. Serum level of solubility LAIR-1 (sLAIR-1) was measured using ELISA. Real-time PCR was used to measure LAIR-1 mRNA expression. Thirty-two healthy children served as the control group.

RESULTSThe percentages of CD19(+)CD20(+) B cells in the ITP group were significantly higher than in the control group (P<0.05). In contrast, the percentage of CD4(+) T cells in the ITP group was significantly lower than in the control group (P<0.05). The expression levels of LAIR-1 on CD4(+) T cells and CD8(+) T cells were significantly lower in the ITP group than in the control group (P<0.05). Serum sLAIR-1 level and LAIR-1 mRNA expression in the ITP group significantly increased compared with the control group (P<0.05).

CONCLUSIONSLAIR-1 expression on CD4(+) and CD8(+) T cells decreases and serum sLAIR-1 level increases in children with ITP, suggesting that LAIR-1 may play an important role in immune imbalance in these children.

CD4-Positive T-Lymphocytes ; immunology ; CD8-Positive T-Lymphocytes ; immunology ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Purpura, Thrombocytopenic, Idiopathic ; immunology ; RNA, Messenger ; analysis ; Receptors, Immunologic ; blood ; genetics ; physiology

OBJECTIVETo investigate the changes and roles of follicular regulatory T cells (Tfr) and follicular T helper cells (Tfh) in the pathogenesis of children immune thrombocytopenia (ITP).

METHODS32 untreated ITP patients, as well as 20 healthy controls were enrolled in this study. The proportion of circulating Tfr and Tfh cells were determined by flow cytometry; real-time PCR was performed to detect the expression of transcription factors and regulatory factors of Bcl-6, c-Maf, Blimp-1 and PD-1 mRNA; ELISA was used to detect plasma concentration of IL-2, IL-6, IL-10 and IL-21.

RESULTS(1)The proportion of Tfh cells were significantly higher (P<0.05), while the Tfr cells and the ratio of tfr/Tfh cells in ITP patients were significantly lower than that in health controls (P<0.05); (2)Correlation analysis showed that the Tfr cells and the ratio of Tfr/Tfh were positively correlated with the platelet counts and negatively with the levels of PA-IgG, while the proportion of Tfh cells was positively correlated with the levels of PA-IgG and negatively with the platelet counts in peripheral blood; (3)Transcription levels of Bcl-6 and c-Maf mRNA in CD4(+) T lymphocytes cells were significantly elevated, the Blimp-1 mRNA in CD4(+) cells and PD-1 mRNA levels of Treg were lower in ITP patients in comparison with healthy controls; (4)The higher Plasma concentration of IL-21, and lower concentration of IL-2 were found in ITP patients.

CONCLUSION(1)The lower proportion of Tfr cells and higher proportion of Tfh cells, as well as the abnormal ratio of Tfr/Tfh might account for the decreased platelet counts to be further involved in the immunological pathogenesis of children ITP; (2)The changes of plasma cytokines IL-2, IL-21 in microenvironment and the over-expression of Bcl-6 mRNA, c-Maf mRNA and the lower-expression of Blimp-1 mRNA in CD4(+) T cells, and over-expression of PD-1 mRNA in Treg cells might be account for the abnormal ratios of Tfr/Tfh cells in ITP patients.

Cell Movement ; Child ; Humans ; Purpura, Thrombocytopenic, Idiopathic ; immunology ; T-Lymphocytes, Helper-Inducer ; immunology ; T-Lymphocytes, Regulatory ; immunology